As mentioned above by TD, the rudder has a lot of authority and [rudder pedals] should be used for directional control; if necessary along with asymmetrical engine thrust .
During the takeoff roll and after landing, the tiller should NOT be used (or only with extreme caution and at low speeds), otherwise the outcome could to be less than desirable.
I heard of inexperienced Twin Otter pilots unexpectedly veering off the runway and damaging the aircraft beyond repair, during take off and/or immediately after landing, because of just that.